From 018951ef40ef6fa1fed258468e429b013fbe67d6 Mon Sep 17 00:00:00 2001
From: Neil Brown <neil@twistedsquare.com>
Date: Wed, 27 Feb 2008 15:13:11 +0000
Subject: [PATCH] Fixed the shift behaviour by moving it out into functions
 like the add and subtract operations already were

---
 backends/GenerateC.hs | 24 ++----------------------
 tock_support.h        | 25 ++++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/backends/GenerateC.hs b/backends/GenerateC.hs
index 7087b54..12a4554 100644
--- a/backends/GenerateC.hs
+++ b/backends/GenerateC.hs
@@ -263,15 +263,6 @@ cgetScalarType A.Timer = Just "Time"
 cgetScalarType A.Time = Just "Time"
 cgetScalarType _ = Nothing
 
-cgetUnsignedType :: A.Type -> Maybe String
-cgetUnsignedType t | elem t [A.Byte, A.UInt16, A.UInt32, A.UInt64] = cgetScalarType t
-cgetUnsignedType A.Int8 = cgetScalarType A.Byte
-cgetUnsignedType A.Int = cgetScalarType A.UInt32
-cgetUnsignedType A.Int16 = cgetScalarType A.UInt16
-cgetUnsignedType A.Int32 = cgetScalarType A.UInt32
-cgetUnsignedType A.Int64 = cgetScalarType A.UInt64
-cgetUnsignedType _ = Nothing
-
 -- | Generate the C type corresponding to a variable being declared.
 -- It must be possible to use this in arrays.
 cgenType :: A.Type -> CGen ()
@@ -853,19 +844,8 @@ cgenDyadic m A.Rem e f = call genFuncDyadic m "rem" e f
 cgenDyadic _ A.Plus e f = call genSimpleDyadic "+" e f
 cgenDyadic _ A.Minus e f = call genSimpleDyadic "-" e f
 cgenDyadic _ A.Times e f = call genSimpleDyadic "*" e f
-cgenDyadic _ A.LeftShift e f = call genSimpleDyadic "<<" e f
-cgenDyadic m A.RightShift e f
-  = do t <- typeOfExpression e
-       (normalT, unsignedT) <- case (cgetScalarType t, cgetUnsignedType t) of
-         (Just x, Just y) -> return (x,y)
-         _ -> diePC m $ formatCode "Attempting to shift non-integer type: %" t
-       if (normalT == unsignedT)
-         then call genSimpleDyadic ">>" e f
-         else do tell ["((", normalT, ")(((", unsignedT, ")"]
-                 call genExpression e
-                 tell [") >> "]
-                 call genExpression f
-                 tell ["))"]
+cgenDyadic m A.LeftShift e f = call genFuncDyadic m "lshift" e f
+cgenDyadic m A.RightShift e f = call genFuncDyadic m "rshift" e f
 cgenDyadic _ A.BitAnd e f = call genSimpleDyadic "&" e f
 cgenDyadic _ A.BitOr e f = call genSimpleDyadic "|" e f
 cgenDyadic _ A.BitXor e f = call genSimpleDyadic "^" e f
diff --git a/tock_support.h b/tock_support.h
index c370a39..2a52fdd 100644
--- a/tock_support.h
+++ b/tock_support.h
@@ -180,6 +180,28 @@ static inline int occam_check_retype (int src, int dest, const char *pos) {
 		return a - (i * b); \
 	}
 
+#define MAKE_SHIFT(type) \
+	static inline type occam_lshift_##type (type, int, const char*) occam_unused; \
+	static inline type occam_lshift_##type (type a, int b, const char* pos) { \
+		if (b < 0 || b > sizeof(type) * CHAR_BIT) { \
+			occam_stop (pos, "left shift by negative value or value (strictly) greater than number of bits in type"); \
+		} else if (b == sizeof(type) * CHAR_BIT) { \
+			return 0; \
+		} else { \
+			return (a << b); \
+		} \
+	} \
+	static inline type occam_rshift_##type (type, int, const char*) occam_unused; \
+	static inline type occam_rshift_##type (type a, int b, const char* pos) { \
+		if (b < 0 || b > sizeof(type) * CHAR_BIT) { \
+			occam_stop (pos, "right shift by negative value or value (strictly) greater than number of bits in type"); \
+		} else if (b == sizeof(type) * CHAR_BIT) { \
+			return 0; \
+		} else { \
+			return (type)(((u##type)a) >> b); \
+		} \
+	}
+
 #define MAKE_ALL_SIGNED(type,flag) \
 	MAKE_RANGE_CHECK(type,flag) \
 	MAKE_ADD(type) \
@@ -187,7 +209,8 @@ static inline int occam_check_retype (int src, int dest, const char *pos) {
 	MAKE_MUL(type) \
 	MAKE_DIV(type) \
 	MAKE_REM(type) \
-	MAKE_NEGATE(type)
+	MAKE_NEGATE(type) \
+	MAKE_SHIFT(type)
 
 //{{{ uint8_t
 MAKE_RANGE_CHECK(uint8_t, "%d")